SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4facfda93116212cee3ec5323b980914edd39fb1144a15192063fc2a837fa143' 
  AND token = 'Ycz6l0IgS+VWV7G1WGT3v1YLRcwwR7rkFueiFVQU3Yc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}